In order to provide output voltages of a thousand or more volts, conventional solid-state high voltage operational amplifiers must utilize a multiple cascode circuit with high voltage transistors between the output of an operational amplifier and the load. Use of high voltage transistors inherently require the use of a high voltage power supply. In addition, such circuits require feedback and bias circuits and protection circuits and often suffer from low d.c. forward sequence gains. Thus, such conventional high voltage operational amplifiers are bulky, costly, have heat disipation problems and are therefore, unsuitable for many present day applications which require compact and inexpensive high voltage operational amplifiers.
The present invention overcomes the foregoing disadvantages and provides an improved high voltage operational amplifier eliminating entirely the requirement of high voltage transistors and a high voltage power supply.